<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<!--点击事件调用方法-->
<input type="button" value="按钮" onclick="fn1()">
<script>
    //无参无返回值
    function fn1() {
        alert("fn1")
    }
    fn1()
    //有参有返回值
    function fn2 (name ,age) {
        alert(name+":"+age)
    }
    fn2("张飞",18)
    //无参有返回值
    function fn3() {
return "我是返回值";
    }
    alert(fn3())
    //有参有返回值
    function fn4(x,y) {
return x*y
    }
    let result = fn4(8,9)
    alert(result)

    //第二种声明方法的方式
    let fn5 = function (name,age) {
    alert(name+":"+age)
    }
    fn5("刘备",30)
    //第三种声明方法的方式
    let fn6 = new Function ("name","age","alert(name+':'+age)")
    fn6("关羽","25")

</script>
</body>
</html>